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title: "661 — 2 equivalent grades, compared"
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AISI / SAE · United States · 2 grades

# 661

The designation 661 is carried by 2 different grades. Compare them on the elements that actually differ, then open the one your print means.

- *Matching grades* **2**
- [*Category* **High-temperature steels · 40 grades**](/categories/high-temperature-steels "Category: High-temperature steels · 40 grades")

[Search](/search "Steel grade search")[Inquiry](/inquiry "Inquiry")

## Which of the 2 do you want?

This name is carried by several grades. The elements shown are the ones whose values actually differ across the set — the ones that decide the question. Values are the source text verbatim; an em dash means no value on file for that element on that grade, not zero.

| Grade | Material no. | Category | Designations | C% | Si% | P% | Cr% | Mn% | Ni% |
|---|---|---|---|---|---|---|---|---|---|
| [X20CrMoWV12-1](/materials/din-en/x20crmowv12-1 "X20CrMoWV12-1") | [1.4935](/materials/material-no/1.4935 "1.4935") 1.4 | [High-temperature steels](/categories/high-temperature-steels "High-temperature steels") | 16 | 0,17-0,24 | 0,10-0,50 | 0,025 | 11,0-12,5 | 0,30-0,80 | 0,30-0,80 |
| [X12CrCoNi21-20](/materials/din-en/x12crconi21-20 "X12CrCoNi21-20") | [1.4971](/materials/material-no/1.4971 "1.4971") 1.4 | [High-temperature steels](/categories/high-temperature-steels "High-temperature steels") | 8 | 0,08-0,16 | ≤1,00 | 0,035 | 20,0-22,5 | ≤2,00 | 19,0-21,0 |

## Not sure which one your print means?

Search the catalogue by designation, material number or composition — every name on this page is itself a way in.

[Search](/search "Steel grade search")[Inquiry](/inquiry "Inquiry")